Method for synthesizing activated carbon analcime from oil shale waste

Abstract

The invention relates to a method for synthesizing activated carbon analcime from oil shale waste, which comprises the following steps of: pretreating the oil shale waste, carbonizing the oil shale waste, dissolving in acid, carrying out hydrothermal reaction and the like to synthesize the activated carbon analcime. The novel composite material composed of the activated carbon analcime is prepared by adopting a hydrothermal synthesis method, the surface area of the activated carbon analcime is obviously larger than that of the oil shale residues, and the activated carbon analcime has good adsorption performance on organic dyes such as methylene blue and can be used as an adsorbent or used for producing the adsorbent, so that a new direction is provided for utilization of the oil shale ash residues; the method has great theoretical and practical significance.

Description

Technical Field

[0001] The invention relates to a method for preparing analcime, and in particular to an application of oil shale slag and a method for synthesizing activated carbon analcime. Background Art

[0002] Oil shale is known as an important alternative energy source in the 21st century. There are about 10 trillion tons of oil shale resources in 33 countries around the world, which is 40% more than coal resources. Oil shale can not only make a variety of chemical raw materials, but its fuel can also be used for power generation and heating. In China, there are two traditional technologies for the utilization of oil shale resources: one is to produce shale oil and fuel gas by distilling oil shale, and the other is to burn oil shale to generate electricity. A plant that processes 5 million tons of oil shale annually can produce more than 3 million tons of oil shale ash every year. Most of the oil shale slag is piled up in the open air. Moreover, the ash produced during the combustion of oil shale cannot be completely collected. About 1-2% of the ash enters the atmosphere, and the dust entering the atmosphere includes about nine heavy metals (namely: As, Cd, Cr, Cu, Hg, Ni, Pb, Zn and V). In addition, it has been monitored that the concentration of heavy metals in the soil and vegetation around the ash dump has an increasing trend. There is no large-scale research on the preparation of activated carbon analcime using oil shale as raw material in my country. In order to protect the environment and promote the sustainable and circular utilization of resources, it is urgent to provide a comprehensive utilization method of oil shale residue and develop a new way to effectively utilize oil shale residue. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides an application of oil shale slag for synthesizing activated carbon analcime, and the method comprises the following steps:

[0004] 1) Oil shale slag pretreatment:

[0005] Grinding of oil shale residues to a particle size range of less than 50 microns;

[0006] 2) Carbonization of oil shale slag:

[0007] Weigh a certain amount of oil shale slag and calcine it in an atmosphere furnace at 500-800°C for 2-5 hours to carbonize the unburned carbon in the oil shale slag;

[0008] 3) Acid dissolution of carbonized oil shale slag:

[0009] A certain amount of carbonized oil shale residue is weighed and added into an acid solution for acid dissolution to dissolve impurities such as iron and magnesium in the oil shale residue; after the acid dissolution is completed, the oil shale residue is washed with deionized water, filtered and dried to obtain oil shale residue with a neutral pH; acid treatment helps to remove impurities and improve the surface properties of the sample;

[0010] Furthermore, in step 1), by comparing different ball milling times, the best effect was achieved when the ball milling time was 1h and the D90 was 10.346 μm. Therefore, the particle size for grinding the oil shale slag is preferably D90 of 10.346 μm.

[0011] Furthermore, in step 3), the acid solution is preferably hydrochloric acid with a concentration of 10-20 wt %; the concentration of the hydrochloric acid is preferably 10 wt %, and the ratio of oil shale slag / acid solution is preferably 3 g / ml.

[0012] Furthermore, in step 3), the drying temperature is preferably 100°C.

[0013] 4) Synthesis of activated carbon analcime:

[0014] The oil shale residue after acid dissolution in step 3) is added to a sodium hydroxide solution, and stirred with a magnetic stirrer at room temperature to obtain a mixed solution; the mixed solution is subjected to a hydrothermal reaction, and after the reaction is complete, it is washed, filtered, and dried to obtain activated carbon analcime; the hydrothermal reaction temperature is 100-150° C., and the hydrothermal time is 10-12 hours.

[0015] Furthermore, in step 4), the concentration of the sodium hydroxide solution is preferably 10-20 wt %; and the stirring time is 3-10 h.

[0016] Furthermore, in step 4), the mass ratio of oil shale slag to sodium hydroxide solution is preferably 1:2.3.

[0017] Furthermore, in step 4), the drying temperature is 60-100°C.

[0018] The activated carbon analcime prepared by the invention has good adsorption performance for organic dyes such as methylene blue and the like, and can be used as an adsorbent or for producing an adsorbent.

[0019] Beneficial effects of the present invention:

[0020] The method for synthesizing activated carbon analcime from oil shale slag proposed in the present invention uses oil shale slag as raw material and adopts a hydrothermal synthesis method to prepare a new composite material composed of activated carbon analcime, which belongs to a comprehensive utilization method of oil shale slag, which not only protects the environment, but also promotes the sustainable and circular utilization of resources. The synthesized composite material was analyzed by several characterization techniques such as XRD, SEM, BET and FTIR. The adsorption effect of the activated carbon analcime prepared by the present invention is much higher than that of the commercially available analcime. The results confirm the successful compounding between activated carbon and analcime. In addition, the surface area of ​​the activated carbon analcime is significantly larger than the surface area of ​​the oil shale slag. The present invention provides a new direction for the utilization of oil shale ash, which has great theoretical and practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1It is a schematic diagram of the overall process of the present invention;

[0022] Figure 2 The XRD diagram of the activated carbon analcime synthesized under the conditions of the embodiment of the present invention;

[0023] Figure 3 The infrared spectrum of the activated carbon analcime synthesized under the conditions of the embodiment of the present invention;

[0024] Figure 4 , 5 6 is a scanning electron microscope image of activated carbon analcime synthesized under the conditions of the embodiment of the present invention;

[0025] Figure 7 This is a scanning electron microscope image of oil shale residue;

[0026] Figure 8 This is the adsorption efficiency diagram of methylene blue solution by activated carbon analcime under different pH conditions;

[0027] Fig. 9 This is the adsorption efficiency diagram of methylene blue solution on activated carbon analcime at different adsorption times;

[0028] Fig.10 This is the adsorption efficiency diagram of methylene blue solution adsorbed by activated carbon analcime at different adsorption concentrations;

[0029] Fig.11 This is the adsorption efficiency diagram of methylene blue solution on activated carbon analcime at different adsorbent dosages. DETAILED DESCRIPTION

[0030] like Figure 1 As shown, this embodiment provides a method for synthesizing activated carbon analcime from oil shale slag, comprising the following steps:

[0031] 1) Oil shale slag pretreatment:

[0032] The material was ground with a planetary ball mill at a speed of 360 revolutions per minute for 40-60 minutes, and then filtered through a 200 mesh sieve to obtain oil shale slag with uniform particle size distribution, and the particle size D90 was 10.346 microns.

[0033] 2) Carbonization of oil shale slag:

[0034] A certain amount of oil shale slag was weighed and placed in a porcelain boat, and calcined in a tube furnace at 600°C for 3 hours to carbonize the unburned carbon in the oil shale slag and form pores in the carbonization.

[0035] 3) Acid dissolution of carbonized oil shale slag:

[0036] 10 g of carbonized oil shale slag was weighed and added into 30 mL of hydrochloric acid solution for acid dissolution, the concentration of hydrochloric acid was 10 wt %, impurities such as iron and magnesium in the oil shale slag were dissolved, and the surface properties of the sample were improved; after the acid dissolution was completed, the solid sample was filtered out from the acid solution, repeatedly rinsed with deionized water until the pH value of the solution became neutral, and dried at 100° C. to obtain oil shale slag with neutral pH;

[0037] 4) Synthesis of activated carbon analcime:

[0038] Weigh 7 grams of sodium hydroxide particles and add them to a 250 ml beaker, pour 50 ml of distilled water to prepare a sodium hydroxide solution; add 20 g of acid-dissolved oil shale residue to the sodium hydroxide solution, stir with a magnetic stirrer at room temperature for 10 hours to obtain a mixed solution; transfer the mixed solution to a high-pressure reaction kettle lined with polytetrafluoroethylene, seal it, and place it in an oven at 120° C. for 12 hours for hydrothermal reaction. After the reaction is complete, the obtained sample is fully washed with deionized water to remove excess sodium hydroxide, and then dried at 60° C. for 12 hours to obtain activated carbon analcime, such as Figure 2-6 As shown;

[0039] contrast Figure 7 It can be seen that the activated carbon analcime prepared by the method of the present invention changes the original morphology of oil shale slag; in terms of specific surface area, the surface area of ​​the activated carbon analcime is 16.3m 2 / g, the surface area of ​​oil shale residue is 7.9m 2 / g, the surface area of ​​activated carbon analcime is significantly larger than that of oil shale slag.

[0040] Adsorption experiment:

[0041] Preparation of adsorption reagent: Use appropriate amount of methylene blue and deionized water to simulate the aqueous solution of organic dye. In order to clarify the effect of organic dye concentration, the content of methylene blue in the test solution varied between 15mg / L-55mg / L, while the content of analyte remained unchanged. The initial concentration used in the experiment was 35mg / L. The adsorbent dosage of the adsorbent was varied in the range of 1g / L-6g / L to study its effect on adsorption. The pH was adjusted from 2-11 using 0.1M hydrochloric acid and sodium hydroxide to detect the effect of pH. At the end of the adsorption experiment, 10ml of MB supernatant was collected, centrifuged at 8000r / min for 3min, and then the concentration of the resulting solution was measured using a UV spectrophotometer. The results are shown in Figure 8-11 As shown, the activated carbon analcime prepared by the present invention has good adsorption performance for methylene blue, especially at pH 7, the adsorption efficiency can reach more than 97%; when the adsorbent dosage is 6g / L, the adsorption efficiency can reach more than 99%.

[0042] The present invention adopts a hydrothermal method to prepare activated carbon analcime, and studies the performance of activated carbon analcime by means of X-ray diffraction (XRD), scanning electron microscope (SEM) and other testing methods, and studies the adsorption efficiency of activated carbon analcime on methylene blue under different adsorption conditions. The adsorption effect of activated carbon analcime prepared by the present invention is much higher than that of commercially available analcime. Scanning electron microscope images show that the synthesized material has both the structure of activated carbon and the structure of analcime.

[0043] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for synthesizing activated carbon analcime from oil shale slag, Features: The steps include: 1) Oil shale slag pretreatment: Grinding of oil shale residues to a particle size range of less than 50 microns; 2) Carbonization of oil shale slag: Weigh a certain amount of oil shale slag and calcine it in an atmosphere furnace at 500-800°C for 2-5 hours to carbonize the unburned carbon in the oil shale slag; 3) Acid dissolution of carbonized oil shale slag: Weigh a certain amount of carbonized oil shale residue and add it to an acid solution for acid dissolution to dissolve impurities in the oil shale residue; after the acid dissolution is completed, wash it with deionized water, filter it, and dry it to obtain oil shale residue with a neutral pH; 4) Synthesis of activated carbon analcime: The oil shale residue after acid dissolution in step 3) is added to a sodium hydroxide solution, and stirred with a magnetic stirrer at room temperature to obtain a mixed solution; the mixed solution is subjected to a hydrothermal reaction, and after the reaction is complete, it is washed, filtered, and dried to obtain activated carbon analcime; the hydrothermal reaction temperature is 100-150° C., and the hydrothermal time is 10-12 hours.

2. The method for synthesizing activated carbon analcime from oil shale slag according to claim 1, Features: In step 3), the acid solution is hydrochloric acid with a concentration of 10-20 wt %; the ratio of oil shale slag / acid solution is 3 g / ml.

3. The method for synthesizing activated carbon analcime from oil shale slag according to claim 1, Features: The drying temperature in step 3) is 100°C.

4. The method for synthesizing activated carbon analcime from oil shale slag according to claim 1, Features: In step 4), the concentration of the sodium hydroxide solution is 10-20 wt %; and the stirring time is 3-10 h.

5. The method for synthesizing activated carbon analcime from oil shale slag according to claim 1, Features: In step 4), the mass ratio of oil shale slag to sodium hydroxide solution is 1:2.

3.

6. The method for synthesizing activated carbon analcime from oil shale slag according to claim 1, Features: In step 4), the drying temperature is 60-100°C.

7. An activated carbon analcime, Features: Prepared by the method described in any one of claims 1 to 6.

8. An activated carbon analcime according to claim 7, Features: As an adsorbent for organic dyes or used in the preparation of adsorbent products for organic dyes.

9. Application of oil shale residue, Features: Used for synthesizing activated carbon analcime, the synthesis method is any one of claims 1-6.

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